<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="./bootstrap-3.4.1-dist/css/bootstrap.min.css">
    <style>
        .container div:first-child {
            background-color: pink;
        }

        .container div:last-child {
            background-color: skyblue;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="col-lg-3 col-md-6">1</div>
        <div class="col-lg-3 col-md-6">2</div>
        <div class="col-lg-3 col-md-6">3</div>
        <div class="col-lg-3 col-md-6">4</div>
    </div>
</body>
</html>